Method of making glass plates



Sqn' \5, 1925. Y 1553773 W. E. HEAL v METHOD OF MAKING GLASS PLATES Filed Sept. 6. 1924 Patented sept. 15, 1925.

` wrnrlmiir E. HEAL,` onwnsHINGToN, `DISTRICT Yor COLUMBIA.

METHOD oF MAKING GLASS PLATES.

VApplication filed September Be it knownthat I, WiLLiAixi VE. HEAL, a citizen of thefUnited-` States,l residing at Washington, in the District of Columbia,

have Vinvented certain 'new` and useful I'nr provements in AMethods of Making Grlass' Plates, of which the followingfis'a' specification. 1 l' This invention relatesto methods of mak- 10. Iing :plate glass, and-more; particularly to :a

method of forming glass plates 'byfusing powdered glass lin a layer' over asupporting Imedium in the natureof a layer of metal Y. which has aflower Ameltingzp'oint thanv the I am aware glass vplates by vthemethodabove outlined wherein a supporting'medium .such astin Withjsuch an apparatus it has been found. y that the surface of themolten metal becomes oxidized and causes considerable troubler'in voperation since'it is very diflicult to entirely 3 4cover the surface ofthe metal` with the glass so as kto substantially'exclude air. y In my rclosed a method and apparatus 'for forming `glass plates wherein' I provide a supporting tray having ak layer of magnesia or quartz arrangedl therein and a layer ofV powdered' glass is spread evenly overy the surface of into a heating .chamber to fuse the glass. `The magnesia or' quartz lwhich 'forms the supporting medium `for the powdered glass obviously has a higherv melting point than' the glass land the latter is fused without dising medium.

An object lof the presentinyention Vis to erally vsimilar to that of my copending ap-v plication above mentioned except that I employ a layer of'fmetal, preferablytin, as the supporting'mediumfor vthe powdered glass,- or previously formedAv sheet of glass, the

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copending application Serial No.VV v660,575 y'filed September 1, 1923, I have disf the quartz .whereupon the trayfis inserted turbing the solidi condition of thesupportwhich may be carried fout ina manner gen` metalhaving a lowerk melting point than the e, 1924., serialY No. Wazaa glass, a veryhigh vaporizing point, and possessing a,liiglier'speciiic lgravity than the jglass. In the practice of themethod I ein- 2ploy a tray in which is placed the supportlnggmedium Aof metal? and theV powdered glass or'glass sheet is adapted to wholly coverthe exposed surface of theinctal so that when ,the latter is melted in the manner kto be describedA oxidation of the surface metal is substantially prevented.

-A further object of the invention is tc providea method as above outlined wherein boththepowdered glass and the'inetal sup- -Aporting medium `may bev highly heated i Y whereby both will melt, after which the of previous attempts to form?v glass,rmetal, and tray may be cooled to a temperature below the 'melting point of the. glasslbut `Vabove thel melting point of the nietalsupporting medium whereby the lat- *ter may bedrawnoff from the tray and the vglass plate removedf` In. the accompanying drawings I have shownf an organization, of apparatus elements particularlyadapted for practicing the processfandforming a part of the pres ent invention.;` 'In this showing-A l,Figure 1 is a verticallongitudinal sectional view of Va forming chamber showing the table' or tray being inserted within the v^Figure 2 is a vertical longitudinal sectionalview of the tray showing a somewhat modifiedmannerof carrying out the method,

Figure 3 is a similar. view showinga further modification,l l

i Figure 4 is a fragmentarv perspective of the tray and associated elements showing a l plate of glass 'formed therein, and,

lFigure 5 is a. detail view showingone manner in which the tray may be tilted when withdrawnV from the chamber.

y Referring to the drawingsthe numeral 1 designates a heating chamber preferably formedof blocksof fire clay having an opening 2 formed in` one wall' and adapted to be closed -by afvertically movable' door -3.' The chamber maybe heated in anys'uitablemanmounted within `thechamber and some outwardly of the chamber,-the lupper portion ofthe rollers being arranged slightly above gas such as nitrogen. When thetray'is po-` the bottom of the yopening 2 as shown in Figure 1.

The numeral y5 designates a tray formed of any suitable material having a very'high melting point such as cast iron and the tray is provided with a peripheral upstanding flange 6. The tray isprovided preferably at its outer end with a pocket 7 communicating with the lower port-ion of the interior of the tray and a coclr 8 is threaded into the tra-y to control Communication Ybetween the pocket 7 and any suitable collecting means. for the molten metal therein, to be described. The tray is adapted to contain a layer 9 ofV molten metal such as tin which has a lower vmelting point than glass, a very high vaporizing point and a higher specific gravity than glass. The metal preferably fills more than one-half the volume of the interior of the tray 5 and is preferably melted when vinitially placed in the tray to provide a smooth upper surface. As shown in Figures 1 to 4 inclusive, a hollow ring 1() is placed within the flange 6 and preferably snugly Vfits the inner walls thereof.

In the practice of the method according k,to the showing in Figure 1, I place a sheet of glass 11 within the ring 10, the sheet 11 9 and glass sheet `11 is inserted into theV chamber 1 by rolling over therollers 4 as shown. The interior of the chamberV 1 is highly heated byany suitable means,vnot

shown, and the greater portion of the air therein is exhausted by pumping into the chamber 1, through the pipe 12, an inert sitioned wholly within the chamber 1, the door 3 is closed and the tray, metal layer 9 and glass 11 are heated until the glass softens whereupon it vassumes a perfectly horizontal position upon the metal 9, which, becomes fluid before the sheet 11 softens. Obviously the metal 9, when melted, presents a perfectly polished 4upper surface which supports the sheet 11 whenl the latter isrsoftenedwso that the lower facegthereof Y, becomes Vhighly polished. v Obviously the softening of the sheet 11 highly polishes the `upper surface thereof whereupon it assumes a. high polishrequired of high grade p-late glass. IVhen the above operation has been completed the tray 5 is withdrawn from the lheating chamber and tiltedv to a vertical pol, sition'in any suitable manner whereupon the molten metal 9 is drawn off through the cock 8 into any suitable collecting receptacle.

It will be obvious thatithe fusing of the i `sheet1lcauses it to-,adheretothelring 10 fthe tray 5 provided preferably centrally thereof with trunnions 13 which may engage supporting members 14 arranged outwardly of the heating chamber after the tray has been moved outwardy from the chamber. It will be obvious that the trunnions 13 may engage arcuate cut-out portions in the supporting members 14 whereupon the tray may be tilted to assume the previously described vertical position to permit the molten metal to be drawn oif.

In Figure 2 of the drawings I have shown a somewhat modified manner of carrying out the method wherein I spread a layer of powdered glass 16 evenly upon the surface Yof the metal 9.

l The tray containing the metaland powdered glass'V 1G is inserted into the heating chamber' 1n the 'manner previously described and is heatedy unitil'the 'f metal becomes fluid and the glass fuses forming a sheet which Iwill have highly polished upper and lowerfaces.v The tray is withdrawn from the chamber iny the manner previously described and the temperature of the tray, metal and glass is reduced to a point below'the melting point of the glass but above that of the metal whereupon the latter may be drawn offfwhile the tray is ina vertical position and the ring G may be* removed with `the sheet of glass therein.

In Figure 3 of the drawings I have shown a method whereby relatively thinsheets of glass may be increased in thickness and the opposite sides of the thickenedsheet or l plate highly .polished to provide a high grade glass plate. In this modified method I place a relatively thin sheet of'lower grade previously formed glass 17 within the ring` 10 and cover it evenly with a layer of powdered glass 18. The tray is then inserted within the furnace and the above described operation carried out rwhereupon the lower glass sheet 17 will soften sufficiently to become highly polished by the fluid metal while the powdered glass 18 will fuse and unite with 1 the sheet 132th@ fluidity ofthe powdered glass 18 causing theupper surfacethereof yto assume a high polish. The tray is then removed from the chamber and the plate of `glass removed in the manner previously dethe pipe 12 while the operation is being carried out and the metal is Vin a molten Vcondition. 'l y It will be'obvious that in the practice of the method as outlined in Figure 2, I may employ patternsl asshown in my copending application Serial No.V 660,575, for making;

v cathedral or so Vcalled stained glass byv forming the layer of owdered glass in the manner described in t e copending application. f

ferred .practice of my understood that thedetails of procedure of Vr It will be Obvious tinta@ glass `plate c formed by either of thepreviously described propn methods may be placed in a' leer and erly' annealed in the usual manner. f

While I have described in detailthe premethods, it is to be the methods vmay berw'idely varied withoutk departing from the s irit of the invention.

or the scope of the su joined claims. Having described my invention, I claim:

stantially horizontal supporting medium Vhaving a lower fusing point vthan that of the glass',and heatingfthe glass and' support-` ing medium tovaztemperature at least as high as the fusingtemperature ofthe glass.

2. The herein described method of mak-v ingvglass plates which consists in placing a layer of glassk on the' 4upper surface `of' a substantially horizontal supporting' medium having a lower fusing point' than thatv of the glass, heating the glass and supporting `medium to a temperature katleast as high as the fusing point of the glass, cooling the glass to a point below its fusing temperature but above the fusing temperature of the `supporting medium, and lremoving said supporting medium from `beneath the glass in a ,fluid condition. y Y Y 3. The herein described method of making glass plates which consists in placing a layer of powdered glass on the upper surface of a substantially horizontal supporting medi.- um having a lower fusing point than that of the glass, and heating the glass and supporting medium in thefpresenceof an inert gas toa temperature atleast as high as the fusing temperatureof the glass."

4. The herein described method of making glass plates whichconsists in placing a layer of glass on and substantially covering the upper surface, of a substantially horizontal metallic supporting medium having a lower lfusing point and higher specific gravity than the glass, and `heating the glass and supporting `medium to a temperature at least as high as the fusing temperature of the glass.

5. The herein 'described method of making glass plates which consists in placing a d a luidcondition. i l. `The herein described method of makf ing glass plates whichA consists in placing a layer of glass on the upper surface of a sub-y 6. The herein described method yof making glass plates which consists in placing a confining ring on theupper surface of a substantially. horizontal supporting medium, placing a ylayer of glass on said supporting medium and substantially filling the space within said ring, the glass having aV fusing point intermediate the fusing points of said ring and supporting medium, heating said ring, glass and supporting medium to a temperature lower than the fusing point of said ring but at least as high as the fusing point of the glass, cooling the glass to atemperature definitely below its fusing point, removing said supporting medium from beneath said glass in a fluid condition, and removing thev glass from said ring. c

7. The herein described method of making glass plates which consists in placing va layer of powdered glass on and substantially covering the upper surface of a supporting medium :having a lower fusing pointthan the fglass, heating the glass and supporting medium to a temperature sufiiciently high to render the glass highly fluid, cooling the glass to a temperature below its fusing point to set it, and removing said supporting medium from beneath the glass in a fluid condition. Y

In testimony-whereof I affix my signature.

, WILLIAM E. HAL.

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